Part 1: Potassium, and Rubidium.
Part 2: Calcium has 20 protons and 20 electrons because the atomic number for calcium is 20 and that determines how many protons there are and in an atom, the number of protons is the same number of electrons. Calcium has about 20 neutrons. I got the number of Neutrons by subtracting the mass number(40.078) and the atomic number(20), I got 20.078. Round to the nearest whole number because you cannot have half or partial neutron. So, Calcium has 20 protons, 20 electrons, and 20 neutrons,
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Answer:
The correct answer will be "
".
Explanation:
We have:
Moles of solute (Na₂Co₃) = 
= 
= 
Now,
The volume of the solution will be:
⇒ 
∴ 
The formula to find the concentration will be:
⇒ 
On substituting the given values, we get
⇒ 
⇒ 
C. quartz and amethyst
Explanation:
Quartz and amethyst can be told apart by their color without performing a streak test on them.
This is because from the given choices, their color is different.
quartz is a colorless
amethyst is purple
- Quartz is silicate mineral purely made of silicon and oxygen.
- Amethyst is a variety of quartz but containing some mineral inclusions that makes its color different.
- Preforming the streak test gives their color to be white.
- This cannot be useful in identifying the minerals they contain.
- Since their natural colors are distinct, it is a more diagnostics tool .
learn more:
Silicate minerals brainly.com/question/4772323
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